Incandescent lamp.



INGANDESCENT LAMP. APPLICATION FILED r113. 24, 1906.

1,010,165. Patented N0v.28, 1911.

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MATTHEW M. MERRITT, OF MIDDLETON, MASSACHUSETTS, ASSIGNOR TO NATIONAL ELECTRIC LAMP COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF NEW JERSEY.

INCANDESCENT LAMP.

Specification of Letters Patent.

Patented Nov. 28, 1911.

Application filed February 24, 1906. Serial No. 302,674.

To all whom it may concern:

Be it known that I, MATTHEW M. MERRITT,

a citizen of the United States, residing at Middleton, county of Essex and State of Massachusetts, haveinvented an Improvement in Incandescent Lamps, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention relates to improvements in incandescent lamps, having more particularly for its object the provision of a lamp. so constructed as to prevent, or render commercially impracticable, its renewal, or, in other Words, the substitution, or attempted substitution, of a new filament for the old one when the latter is burned out or otherwise rendered useless or inefficient.

It is a common practice to purchase at a relatively slight cost high grade lamps thus burned out, open the end or tip of the lamp and replace the old filament with a fresh one. The new filament having been attached to the leading-in wires, the lamp is exhausted by the usual process, the bulb sealed up, and the renewed or converted lamp in condition again for use. This renewing process is frequently conducted by irresponsible persons lacking the necessary skill and knowledge in the art and employing inferior materials, so that its product, in any event an inferior one, is very often a low grade lamp, though having every appearance of a high grade one.

My invention aims to correct this practice, preventing possible injury to the reputation of the maker of the original lamp and deception of the public as well.

My invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one or more specific embodiments thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings,-Figure 1 shows a lamp embodying one form of my invention and Fig. 2 shows a modification thereof.

Referring to the drawings and to the embodiment of my invention which I have selected for illustration, there is shown a common form of incandescent lamp provided with the usual glass bulb a, cemented I or otherwise secured in the usual fashion to and within the metal socket b and having the usual form of stem 0, through which pass the leading-in wires (1, terminating in l the usual sealed-in platinum ends 6, the latter connected to the filament 7".

One of the characteristics of an old or burned-out lamp, and invariably where it has been used any length of time, is a darkening or clouding of the bulb, which is caused by a deposit of finely divided matter thrown off by the filament or joints during incandescence. This deposit is a considerable factor alone in reducing the effective candle power of a lamp and its removal constitutes one of the usual and first steps in the bulb tip. This is ordinarily accomplished by subjecting the lamp, while the latter is slowly revolved, to some intense heat, such torch. The heat which is usually imparted to the lamp and necessary to volatilize and drive off the solid deposit is probably not less than 500 or 600 Fah., and, of course, abnormally in excess of any heat to which customary and intended use and greatly in excess of the maximum heat which can be interiorly imparted to the bulb by the incandescent filament. For example, the heating of the bulb of an ordinary sixteen candle power lamp can scarcely exceed 150 Fah. even when the filament is carrying the maximum current of which it is capable.

process or other conditions pertaining thereto may be availed of or other means for utilizing them employed, in the described embodiment of my invention I take advantage of the abnormally high degree of heat which is required to carry out the renewing 1 process and particularly the step which involves the removalof the deposit as above described. I utilize the conditions pertaining thereto by causing the violent heat to work injury to the lamp, and preferably to the walls thereof which inclose the lamp space. This may be accomplished in various ways, but in Fig. 1 I have shown a lamp provided with the interior member g, which through its expansion is adapted to l cause injury to, and herein fracture or puncture of the stem or other walls of the renewing process after the opening of the as the heat of an alcohol or hydrogen vapor- Although other steps of the renewing the lamp bulb is ever subjected during its lamp space. As illustrated in Fig. 1, the expansion or fracturing member 9 comprises a preferably metallic piece in the form of a ring and constructed of some material such as brass or aluminum, which has a relatively high coefficient of expansion as compared with the glass of the stem. Such ring may be readily inserted in the stem during the original construction of the lamp and secured therein in any suitable fashion, as by cementing. It can readily be given such a fit relatively to the interior of the stem as to have no harmful effect thereon for the expansion due to the heating of the lamp in ordinary use, while readily effecting the fracture of the stem when the lamp is heated excessively as described in the burning out step of the renewal process.

The fracture of the stem which follows the attempted renewal of the lamp, clue to the violent and abnormal heating which the burning out or other steps thereof calls forth, effectually prevents its commercial renewal, and this is true although the fracture causes the smallest puncture only of the glass, for it will be impossible thereafter to maintain a commercial vacuum within the lamp space.

It is not only immaterial that the particular form of expansion or fracturing member illustrated in Fig. 1 be employed, but the precise location there shown is also unnecessary to my invention.

In Fig. 2 I have shown the annular expansion member 9 so located as to expand under the application of intense heat against the glass walls of the bulb proper to fracture the latter. This ring is herein shown as snugly fitting a grooved recess formed in the neck of the bulb so as to hold the ring from displacement therein and giving the lamp an appearance but little different from a lamp of ordinary construction.

It is to be understood that while I have ment space and fracture the same 011 the abnormal heating of the lamp.

2. A non-renewable incandescent lamp having means for fracturing the glass walls of the filament space on the attempted rcnewal thereof, said means comprising a metallic expansion member having a relatively high coefficient of expansion as compared with glass, said member being located to contact with the glass walls of the filament space to fracture the same on the abnormal heating of the lamp.

3. A non-renewable incandescent lamp having means for preventing its renewal comprising a metallic expansion member for causing injury to the lamp through violent heating thereof.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

MATTHEW M. MERRITT.

Witnesses:

NINA B. SHIRLEY, THOMAS B. BOOTH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

